How To Stop Grandma’s Wheelchair If She Goes Out Of RC Range

January 26, 2014 by Kristina Panos 26 Comments

Okay, so he doesn’t have Grandma riding in it that we know of, but [zim] recently decided to turn a Jazzy mobility chair into “a radio-controlled platform for mischief”. RC offers more range than wifi or bluetooth, and he was able to find a reasonably priced secondhand radio on Craigslist. However, he found out that in the event of signal loss, the receiver keeps sending the last commands to the speed controller. [zim] didn’t want his 150 lb (68kg) mischief platform getting loose, so he devised a fail-safe that cuts power to the motor when the signal is lost.

[zim] discovered that the receiver returns channel 3 (the throttle) to a preset condition whenever the signal is lost. He used a 24V HVAC relay controlled by an Arduino Nano to sample the PW on channel 3 and shut it off when either the throttle or the signal are cut.

If Grandma is feisty, you could build this caged-in version with a shopping cart.

Continue reading “How To Stop Grandma’s Wheelchair If She Goes Out Of RC Range” →

DIY Curved Display Makes Use Of Cool Thermochromic Properties

January 24, 2014 by James Hobson 18 Comments

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[Marin Davide] was on a mission. A mission to build his own curved display screen, using an Arduino, nichrome wire, and thermochromic liquid crystal ink.

The prototype he’s designed uses a sheet of plastic coated in thermochromic ink, curved on an MDF frame. This particular thermochromic ink turns bright blue when heated to around 27°C.

To display digits, he’s created tiny segments of the 7-segment display by wrapping the nichrome wire around pieces of cardboard, which then have been glued to the back of the display. Each of these is controlled separately from his Arduino Mega. He muses that you could also make a rudimentary dot matrix display with this — it would be interesting to see what kind of resolution you could obtain!

To see more photos check out the original DesignNews post linked above. We’re not sure why the bulk of the details are only available in this PDF. If we’re just missing a direct link to the original project page let us know in the comments and we’ll update the post.

Interested in more thermochromic black magic? How about these awesome temperature sensitive photos? Or what about a digital clock face, illuminated by heating resistors?

HackPhx Winter 2014 Hackathon Winners

January 24, 2014 by Todd Harrison 9 Comments

The HackPhx Winter 2014 hackathon was held at Heatsync Labs hackerspace in Mesa, Arizona, USA. The advertised theme was “Arduino Wearables”. Participating attendees were randomly placed on teams evenly distributed by their disclosed skills across all teams. There were 10 teams with 4 to 5 members per team competing for two winning spots.

Each team had to build an amazing wearable project utilizing the secret ingredient which was Seedstudio’s Arduino-compatible Xadow wearable platform and add-ons. The Xadow is similar to the Arduino Leonardo and participants used an Arduino cross compatibility and pin mapping chart to assist in development.

Top prize was the Judges’ prizes for the best completed and documented Xadow wearable team project. The second prize was the Jury’s prize given to the team project that the other teams liked the most regardless of event criteria.

Read more about the winning teams and watch their presentations after the break.

Continue reading “HackPhx Winter 2014 Hackathon Winners” →

All-Terrain RC Car Has More Torque Than Your Grandpa’s Wheelchair

January 23, 2014 by James Hobson 31 Comments

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[Charles] and his brother have been members of their school’s FIRST robotics team for many years, and using some of the knowledge they acquired during it, they have put together this awesome all-terrain, super over-powered, RC car — and soon to be robot.

It’s built like a tank using 1″ square steel tubing and custom corner brackets made of 1/8″ thick steel. Heavy duty U-bolts hold the over-sized 5/8″ axles, and everything is driven using #35 roller chain. A large 12V sealed lead acid battery powers two CIMs (FIRST Robotics motor) with the AndyMark CIMple gearbox — these give the car tons of torque, and it can even do wheelies!

The really cool part of this project is the method of remote control. He’s using a regular old Xbox controller that an Arduino Uno listens to through a USB host shield and the original Xbox USB receiver. Simple, but totally effective.

The project is not yet complete, and he’s planning on fully equipping it with lights, a larger battery, a roll-cage, a camera system, and some kind of manipulator tool. Check out the test drive video after the break!

Continue reading “All-Terrain RC Car Has More Torque Than Your Grandpa’s Wheelchair” →

Capacitance Measurement With The Arduino Uno

January 22, 2014 by James Hobson 25 Comments

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Have you ever found the need to measure the capacitance of a capacitor? No multimeter handy (for shame)? Well, as it turns out you can actually measure capacitance using your Arduino Uno, with no external components, and only ~20 lines of code.

[Jonathan Nethercott] does an excellent job explaining a capacitance test circuit which uses a reference capacitor to calculate the unknown capacitance. He further explains that, with the Arduino Uno, you can remove the reference capacitor from the circuit, and simply use the stray capacitance present in the board and microcontroller, which can be calculated. This results in the test circuit being as simple as plugging in your capacitor to pins A0 and A2. Continue reading “Capacitance Measurement With The Arduino Uno” →

Body Of A Trinket, Soul Of A Digispark

January 22, 2014 by Adam Fabio 12 Comments

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Adafruit’s Trinket and digiStump’s Digispark board are rather close cousins. Both use an ATtiny85 microcontroller, both have USB functionality, and both play nice with the Arduino IDE. [Ray] is a fan of both boards, but he likes the Trinket hardware a bit better. He also prefers the Digispark libraries and ecosystem. As such, he did the only logical thing: he turned his Trinket into a Digispark. Step 1 was to get rid of that pesky reset button. Trinket uses Pin 1/PB5 for reset, while Digispark retains it as an I/O pin. [Ray] removed and gutted the reset button, but elected to leave its metal shell on the board.

The next step was where things can get a bit dicey: flashing the Trinket with the Digispark firmware and fuses. [Ray] is quick to note that once flashed to Digispark firmware, the Trinket can’t restore itself back to stock. A high voltage programmer (aka device programmer) will be needed. The flashing process itself is quite a bit easier than a standard Trinket firmware flash. [Ray] uses the firmware upload tool from the Micronucleus project. Micronucleus has a 60 second polling period, which any Trinket veteran will tell you is a wonderful thing. No more pressing the button and hoping you start the download before everything times out! Once the Trinket is running Digispark firmware, it’s now open to a whole new set of libraries and software.

Final Key : A Mooltipass-like Device

January 21, 2014 by Mathieu Stephan 5 Comments

Since the Hackaday community started working on our offline password keeper, Mooltipass, we’ve received several similar projects in our tips line. The Final Key may be the most professional looking one yet. Similarly to the Mooltipass, it is based on an Atmel ATMega32U4 but only includes one button and one LED, all enclosed in a 3D printed case.

The Final Key is connected to the host computer via USB and is enumerated as a composite Communication Device / HID Keyboard, requiring windows-based devices to install drivers. AES-256 encrypted passwords are stored on the device and can only be accessed once the button has been pressed and the correct 256 bit password has been presented through the command line interface. Credentials management and access is also done through the latter. Unfortunately, the Arduino source code can’t be found on [cyberstalker]’s website, so if you see interesting features that you would like to be integrated in Mooltipass you may send us a message to our Google Group.